Means for controlling the value of an electric current



g- 5, 1930- s. RUTTENBERG 1,772,193

"EARS FOR CONTROLLING THE VALUE OF AN ELECTRIC CURRENT Filld Oct. 11. 1928 Ticiiw. j y

P INVENTOR $1 ATTORNEYS Patented Aug. 5, 1930' v 1,772,193

UNITED STATES PATENT OFFICE SAMUEL BUTTENBERG, OF BROOKLYN, NEW YORK MEANS FOR CONTROLLING THE VALUE OF AN ELECTRIC CURRENT Application filed October 11, 1928. Serial No. 311,769.

This invention relates to means for conunderstood reference is made to the accomtrolling the value of the current in an e1ecpanying drawing which illustrates by way trical circuit. of example two embodiments of the inven- One means for this purpose which is in tion and in which general use in radio operation comprises a Figure l is an illustration of a circuit conballast resistance which is placed in the cirtaining a ballast resistance according to prescuit in series with the load. A property of a ent practice.

ballast resistance is that it increases in re- F lgure 2 is an illustration of means for vasistance upon an increase of current flowing rying a resistance 1n an electrical circult; 10 therethrough, the commercial ballast resist- Figure 3 is an illustration of one form of ances being adapted to increase approximy invention showing a ballast resistance in mately 100% in resistance with a 10% change combination with the means illustrated in in the current which they are intended to Fig. 2.

carry, Figure 4 is a modified form of my inven- 15 Owing to the fact that ballast resistances tion. according to present practice are placed in Referring to Figure 1 of the drawings, the circuit in series with the load, a wattage a supply voltage is provided for the load 1 of a comparatively large amount is consumed by a generator 2, a ballast resistance 3 being by such resistances. For instance if a variaprovided in series with the load 1. I tion in the supply voltage of from 100 to 125 Presuming that the circuit consumes 1O is to be taken care of in a circuit in which amperes and that the supply voltage varies the limit of current variation is one ampere between 100 and 125 volts then the ballast in a normal supply of ten amperes, the balresistance 3 must be able to consume approxilast resistance must be such that at a line mately the addltional 25 volts to keep the 2 voltage of 100 the lost volts across the ballast load voltage substantially constant.

resistance will be 25 volts so that by a change As previously stated the property of a comin its resistance of 100% due to a change in mercial ballast resistance is such that it incurrent flow of one ampere the increase of creases approximately 100% in resistance 25 volts in the supply circuit can be taken with a 10% change in current; thus in order 30 care of and consumed by the ballast resistthat the additional 25 volts will be consumed ance. Thus for a constant load voltage of by the ballast resistance by a change of cur- 75 volts the voltage drop across the ballast rent from 10 amperes to 11 amperes, the inresistance will have a value equal to one-third itial voltage lost across the ballast resistance of that of the load voltage while the voltage must be 25 volts. The approximate results 35 drop across the ballast resistance with a line obtained by a circuit such as that illustrated voltage of 125 volts will have a value equal to in Fig. 1 ignoring the effect of the small rise two-thirds of that of the load volta e. in voltage across the load are shown in the The object of the present invention is to following table:

effect a control of the current through a cir- 40 cuit by means which will consume only a Line voa Volta,

comparatively small wattage. voltage Cum! $533 at load According to one feature of this invention the ballast resistance is provided in a 100 10 25 75 circuit in parallel with the load and such 11 75 45 ballast resistance is associated with means which is adapted to vary a resistance in the It will be clearly seen from this table that circuit, the variation in such resistance being with a supply voltage of volts the ballast proportionately higher than the variation in resistance consumes a wattage which is subthe voltage of the supply circuit. stantially one-third of that consumed by the 50 In order that the invention may be clearly load and that when the supply oltage is 125 100 volts the ballast resistance consumes a wattags which is substantially two-thirds of that consumed by the load.

This considerable consumption in the wattage of the circuit by the ballast resistance is due to the fact that the ballast resistance is in series with the load and that the full current passes through such ballast resistance.

According to the present invention the ballast resistance is arranged in parallel with the load and is so connected that only a small current relatively to the full load current passes through the ballast resistance. Such ballast resistance is arranged so as to control means which will cause a suiiicient variation in a resistance provided in the main circuit as to keep the load voltage substantially constant.

Any suitable means for controlling a resistance in the load circuit may be provided in combination with the ballast resistance, such as for instance the means illustrated in Fig. 2 of the drawings.

Referring to this figure a supply voltage for the load 1 is provided by the generator 2 and a resistance a, such as a carbon pile, which is maintained under compression by means of a spring armature 5, is provided in the circuit in series with the load. A solenoid 6 is also provided in the circuit, this solenoid being in parallel with the load and being in associated relation with the armature 5 so that the pressure exerted by the armature 5 on the carbon pile a will be varied by any change in the value of the current flowing through the solenoid 6. In this construction, however, the variation in pressure on the carbon ile would vary directly with the variations 1n the line voltage and such construction in itself would not effect such a control of the circuit as would maintain the load voltage substantially constant.

According to one form of the present invention as illustrated in Fig. 8 of the drawings, a ballast resistance 7 is connected in parallel with the solenoid 6. A comparatively high resistance 8 is connected between the junction point 9 of the ballast resistance 7 and solenoid 6 and the supply line 10. Assuming that the ballast resistance 7 has a voltage drop across it of one volt when the line voltage is 100 volts, that the resistance 8 is so chosen that the current flowing therethrough is one ampere and that the resistance of the solenoid 6 is approximately 100 ohms, then the current flowing through said solenoid 6 1 of that flowing will be approximately small voltage drop across such ballast resistance. lVith an increase of 10% in the current flowing through the ballast resistance, however, due to an increase in the line voltage to 110 volts, the voltage drop across such resistance will increase 100% owing to the property of ballast resistances as previously stated; thus the drop in voltage across the ballast resistance will be increased to practically two volts. This voltage drop of 2 volts will also be the voltage drop across the solenoid 6 since it is in parallel with the ballast resistance 7 and since the resistance of this solenoid is constant the current therethrough will also increase 100% and will be approximately .02 amperes.

The current flowing through the solenoid 6 willtherefore vary substantially 100% for a change in the line voltage of 10%. Consequently the pull on the armature 5 will increase 100% and a substantially great change in the resistance of the carbon pile 4 can be effected by a comparatively small change in the line voltage. Thus by a suitable construction of the carbon pile t the load voltage applied to the load 1 can be maintained substantially constant.

With this construction only a small current passes through the ballast resistance as compared with that which passes through the load 1, and thus the wattage consumed by the ballast resistance 7 will be comparatively small as compared with that consumed by the load.

The resistance controlled by the solenoid 6 may be of any suitable kind and this resistance may be such that when the supply voltage is at its minimum, the resistance in series with the load will be practically negligible.

Other means than a solenoid and armature for controlling the resistance in series with the load may be provided and as an example of a further method of controlling such resistance reference is made to Fig. 4 of the drawing. In this figure the ballast resistance 7 and the resistance 8 are provided in series in a circuit parallel with the load circuit and the ballast resistance 7 is located within an air chamber 11 which is associated with the carhon pile 1 in such manner that an expansion of the air in such chamber caused by a variation in the heating effect of the ballast resistance 7 due to its variation in resistance, will effect a variation in the pressure applied to the carbon pile. The variation in the pressure applied to the carbon pile by the variation of the pressure of the air in the chamber 11 will be correspondingly much greater than the variation in the resistance of the ballast resistance 7 and thus the volume of air enclosed within the chamber 11 may be so chosen that the cor- The modifications described and illustrated in the specification are given by we of example only and it will be obvious to t ose skilled in the art that other means associated with a ballast resistance arranged in the circuit parallel with the load can be devised for effecting the desired control of the load volt- What I claim is 1. Means for maintaining the current in an electrical circuit substantially constant comprising a ballast resistance in arallel with the load of said circuit, a varia le resistance in said circuit, and means associated with 5 said ballast resistance which is adapted to be influenced by the change in the value of such ballast resistance due to a change in the current flowing therethrough, for controlling the value of said variable resistance.

2. Means for maintaining the current in an electrical circuit substantially constant comprising a variable resistance within said circuit, a ballast resistance in parallel with the load of said circuit, a solenoid in parallel with said ballast resistance and means adapted to be influenced by the change in the current flowing through said solenoid for effecting a variation of the amount of said resistance.

80 3. Means for maintaining the current in an electrical circuit substantially constant comprising a resistance in said circuit, a ballast, resistance in parallel with the load of said circuit, a solenoid in parallel with said ballast resistance, a resistance interposed between said ballast resistance and solenoid, and said circuit, and means influenced by the change in the value of the current flowing through said solenoid for effecting the variation in 40 the value of the resistance in said circuit.

4. Means for maintaining the current in an electrical circuit substantially constant comprising a solenoid in parallel with the load of said circuit, a ballast resistance in parallel with said solenoid, a resistance interposed between said solenoid and ballast resistance, and said circuit, an armature adapted to be influenced by the change in the value of the current flowing through said solenoid, a resistance in said circuit, and means whereby movement of said armature will effect a variation in the value of said re sistance in said circuit.

5. Means for maintaining the current in an electrical circuit substantially constant comprising a ballast resistance in parallel with the load ofsaidcircuit,aresistance in said circuit comprising a carbon pile and means influenced by the change in the ballast resist- 69 ance due to a change in the current flowing therethrough for controlling the pressure exerted on said carbon pile to vary the resistance thereof. a

In testimony whereof I aflix my signature.

SAMUEL RUTTENBERG. 

